polarization oppolsweep → image2dimport fullseye as fs; fs.ledger.polarization_separate(images, angles_deg=(0.0, 45.0, 90.0, 135.0), max_violation_frac=0.0) (実装を直接呼ぶなら import specularity; specularity.polarization_separate(images, angles_deg=(0.0, 45.0, 90.0, 135.0), max_violation_frac=0.0)、台帳から引くなら opsspecular.get("polarization_separate"))fullseye.ledger.polarization_separate(...) は宣言 out 型 image2d の値だけを返す(本体は補助情報も返す)。捨てられた側が要るときは fullseye.ledger.polarization_separate.raw(...)、または specularity.polarization_separate を直接呼ぶ。Split a polariser sweep into its unpolarised and linearly polarised radiance. → (diffuse, specular), both (H, W).
Fitting I(t) = 0.5 (S0 + S1 cos 2t + S2 sin 2t) per pixel gives
I_min and I_max in closed form, and the classical separation
(Wolff & Boult 1991; Nayar, Fang & Boult 1997) reads
``diffuse = 2 * I_min`` (the unpolarised radiance)
``specular = I_max - I_min`` (the linearly polarised radiance)
with diffuse + specular = I_min + I_max = the total scene radiance, so
nothing is lost or invented. Round-tripping
:func:polarization_render through this operator returns the inputs with a
maximum absolute error of 3.9e-16 for the four angles of a
division-of-focal-plane sensor and 4.4e-16 for a bare three-angle sweep
(measured in tests/test_specularity.py).
Read the names as shorthand. What is recovered exactly is the
unpolarised and polarised parts. Calling them diffuse and specular assumes
diffuse reflection is unpolarised and specular reflection is fully linearly
polarised — true near Brewster’s angle for a dielectric, false at normal
incidence, where the specular reflection is unpolarised and this operator
returns all of it as “diffuse”, and unreliable for metals. The polarisation
route is complementary to the colour route
(:func:specular_diffuse_split), not a replacement: it needs no illuminant
colour and works on textured, multi-material surfaces, but it needs a
favourable geometry.
max_violation_frac is the fraction of pixels allowed to fit a negative minimum radiance before the call fails. The default 0 is fail-closed: a negative fitted minimum means the modulation exceeded the mean, which no analyser can produce, and it usually means the frames and angles_deg are out of order. Raise it to clamp sensor-noise-level violations to zero as a deliberate, recorded choice.
Raises ValueError: images is not an (N, H, W) stack of at
least 3 frames, or exceeds :data:MAX_LIGHTS / :data:MAX_STACK_ELEMENTS;
angles_deg does not match the frame count or leaves the fit
rank-deficient (two angles equal modulo 180); more than
max_violation_frac of the pixels fit a negative minimum.
py -3.11 examples/poc_polarization_specular.pypy -3.11 examples/specular_photometric.pyimage2d を入力に取れる)polarization)polarization_render · polarization_dolp_map · polarization_stokes
Provenance: specularity.py — SPECULAR operator registry. この per-op ノートは tools/opdocs.py md が自動生成(手編集しない)。
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.